Are either of your other suits from this tailor? If not, it would be dumb to purchase 5 suits from him at once. Purchase 1, and when it comes back, make changes to the next you purchase. Once you get the perfect fitting suit, order as many as you want.
In terms of patterns and colors, here's my list of what you need, in a very particular order:
1. Solid Navy
2. Another solid grey (I'm not sure if your current grey is charcoal. If it is, go medium grey here. If it isn't, go charcoal here)
3. Tan (you'll be doing most of your work in the summer for the next couple of years, so its a good option)
Outside of these 3 options, you can start playing with colors and patterns, although I'd stay in shades of grey for now. You may look into having a couple of sportcoats and trousers made in place of the last 2 suits - maybe a navy blazer and your brown POW pattern that you want for coats, and a medium grey and charcoal pair of trousers.
Oh, and where are you digging up ~$5,000 for suits in your first year of law school? Dealing in black-market meds for ADHD?